AT PRESENT, THE PART OF ANY TEACHER EFFECTIVENESS CRITERION THAT CAN BE PREDICTED WITH A SELECTION TEST IS PROBABLY IRRELEVANT TO TEACHER COMPETENCE. TESTING THE VALIDITY OF PREDICTORS OF TEACHER COMPETENCE IS IMPOSSIBLE BECAUSE IT WOULD REQUIRE HIRING A SIZABLE RANDOM SAMPLE OF ALL WHO APPLY FOR POSITIONS, WITHOUT PRIOR SCREENING. FURTHER, TEACHER APTITUDE TESTS WRONGLY ASSUME THAT THE FACTORS IN SUCCESSFUL TEACHING OPERATE PRIOR TO THE START OF TEACHING IN A SPECIFIC SCHOOL OR SCHOOL SYSTEM. INSTEAD, TEACHING BEHAVIOR PROBABLY VARIES WITH THE TEACHING SITUATION. ACCORDINGLY, AN ACHIEVEMENT RATHER THAN A PREDICTIVE MODEL SHOULD BE USED IN HIRING NEW TEACHERS. PAST LEARNING (E.G., AS MEASURED BY COLLEGE GRADES) IS ONE SUCH MEASURE. TEACHING PERFORMANCE IS ANOTHER ACHIEVEMENT MEASURE. THAT IS, IF, AFTER ONE YEAR, THE PROBATIONARY TEACHER HAS NOT LEARNED TO TEACH, HE SHOULD NOT BE REHIRED. THIS DOCUMENT APPEARED IN GILBERT, H.B., AND LANG, G., "TEACHER SELECTION METHODS" NEW YORK, 1967. (RD)